The urgent of creating the intelligent systems for revealing different kinds of regularities and decision-making in the problem area of pipeline technical condition diagnostics is considered. The technical condition diagnostics of pipeline is strongly dependent on the pipeline parameters, hydrodynamic characteristics of the pipeline-transported substance and that of environment (ambient medium). The advisability for the construction of the intelligent system for the pipeline technical condition diagnostics (IS PTCD) based on intelligent instrumental software (IIS) IMSLOG ambient medium, aimed at revealing different types of regularities in data and knowledge, decision-making and its justification with using cognitive tools, is shown. The matrix way of data and knowledge representation in the problem area and the main stages of IS PTCD constructing based on IIS IMSLOG IS PTCD are given. This will allow to reveal different types of regularities in data and knowledge on the base of the features that influence on the technical condition of the pipeline and, as well as make-decisions of the diagnostic and repair-prophylactic character. IS PTCD is essentially useful for the engineers in the problem area of pipeline-transported substance for decision-making and its justification with using cognitive tools, as well as for research activities and also for student training programs in the problem area.